One example of such a feedback mechanism is described in European Patent Application EP-A-0 607 580 (Selker/IBM) wherein a feedback signal is generated on status information associated with a cursor, such status information including the window handle of the cursor. An indicating rod mechanism is described in which a rod is attached to an actuator at one of its ends: a transitory feedback signal generated by the host computer system on the basis of status information activates the actuator to apply a force to the indicating rod. This rod, which may be mounted in a pointing stick device amongst the keys on a keyboard to the host computer system, or within a mouse cursor control, is arranged such as to press against the finger tip of a user on activation of the actuator connected to the opposite end of the rod. By activation on the basis of status information, such as to indicate by movement of the rod such features as window boundaries and handles, the system of EP-A-0 607 580 aims to enhance a user's perception of exactly when the cursor is in a position to operate or manipulate features displayed on screen without having to slow down movement of the cursor about the screen--either to watch for a change in the form of the displayed cursor to indicate location or as a result of the feedback being provided in the form of physical resistance to movement of the cursor control.
Alternative forms of feedback accompanying cursor movement are described in U.S. Pat. No. 5,186,629 (Rohen/lBM) which describes a computer interface for blind and partially sighted users. Cursor location and selection of menus is indicated by audio feedback including tone generation and speech synthesis. In addition, tactile feedback is provided in the form of a mild AC current passed to the user's hand through a pad on the mouse. In this system, the audio and tactile cues assist the user to build a mental picture of the user interface.
A problem with both of the above systems is their reliance on specific authoring for the user interface presentation in order to provide the cursor status information, such as when the cursor is positioned over a window handle or actuating icon, in order to trigger the tactile or other feedback generation. As tactile and other feedback mechanisms become more prevalent, software packages including the necessary cues for actuation of such mechanisms will become more widespread. With each being presently reliant on the other, user acceptance of tactile and other feedback mechanisms as expected or required features may be slow in coming.